IMAP vs POP3 E-Mail

If you contact support regarding an e-mail problem one of the questions we will ask you is how you are accessing your e-mail. If you are using a client such as Outlook, Outlook Express, Thunderbird, Mac OS X Mail, or any other modern e-mail application we will ask if you are using POP3 or IMAP for your incoming e-mail.
There are pros and cons to both methods, but with some careful consideration of what is most important to the user(s) you can make a (well) informed decision.

IMAP: Internet Message Access Protocol

IMAP has seen a huge increase in everyday use within the past few years for several reasons.

• Pros:
  1. All mail is stored on the server.
  2. Messages will appear the same way every time you set up a new e-mail client, no need to move messages.
  3. You can switch between an e-mail client and webmail at any time and still have the same messages.
  4. If your computer crashes and you lose the data stored on your hard drive your e-mail is still safe, because it is stored on the server.
  5. Makes it easier to access your e-mail using a smartphone because the messages are not removed from the server.
• Cons:
  1. Your mail is only available on the server, so you may not be able to interact with old messages if you are unable to connect to the internet. Some mail clients have optional settings that can help with this problem, but not all of them.
  2. In the event of catastrophic server hardware failure you could potentially lose some e-mail (but you also have this same risk when using POP3 to download messages to your local computer).
  3. Folders may appear slightly different in your e-mail client using IMAP instead of POP3. This is because the folders are stored on the server instead of locally on your computer.

Most modern webmail interfaces use IMAP to display your account’s e-mail.

POP3: Post Office Protocol, version 3

POP3 is the third version of the Post Office Protocol, and is more commonly used by dial-up Internet Service Providers (ISPs) because POP3 tends to work better on slower internet connections. Instead of having the server do most of the work managing messages (IMAP) the POP3 protocol downloads the messages to the local computer and then manages them
on your computer’s hard drive. Some dial-up ISPs only provide POP3 e-mail access and do not allow IMAP connections.

• Pros:
  1. If you want to manage your e-mail through one main interface POP3 can put all of your messages in one place.
  2. Messages are stored locally so you can always access your e-mail, even when you can’t get online.
  3. Opening attachments is generally easier with most clients because the attachments are downloaded with the message simultaneously.
  4. Because your messages are downloaded to your computer your disk space limits are only defined by the size of your computer’s hard drive.
• Cons:
  1. Malicious javascript, viruses, and other malware has a better chance of infecting your computer because each message is 100% local.
  2. If your local computer has the only copy of your e-mail then you risk data loss if your hard drive fails and you don’t have proper backups. Servers usually tend to have better backups available.
  3. E-mail clients using POP3 can be set to leave messages on the server, but as your mailbox on the server grows in size it will take longer and longer for the client application to check for new e-mail (because it will have to check what it has download against what is on the server and then download the new messages).

POP3 is still the most commonly used e-mail protocol because of its simplicity when run in its most basic configuration and its age/reliability. The more complicated a protocol or service is the more likely it is to create more complex support situations.

Making Your Choice

Deciding which e-mail protocol is right for you is entirely dependent upon your needs and what you are doing with that particular e-mail account.
Strong cases for IMAP: